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Muscle Origins, Insertions, and Actions in Anatomy & Physiology

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Terms in this set (29)

  • Teres Major

    Origin: Posterior surface of scapula at inferior angle.
    Main action: Extends, medially rotates, and adducts arm.

  • Biceps Brachii

    Origin: Short head: Coracoid process of scapula; Long head: Supraglenoid tubercle of scapula.
    Main action: Flexes elbow joint and supinates forearm.

  • Brachialis

    Origin: Anterior distal surface of humerus.
    Main action: Major forearm flexor (flexes elbow).

  • Triceps Brachii

    Origin: Long head: Infraglenoid tubercle of scapula; Lateral head: Posterior shaft of humerus; Medial head: Posterior humerus distal to radial groove.
    Main action: Powerful forearm extensor.

  • Brachioradialis

    Origin: Lateral supracondylar ridge at distal end of humerus.
    Main action: Synergist in forearm flexion.

  • Forearm flexors

    Origin: Medial epicondyle of humerus.
    Main action: Flexes wrist and digits.

  • Forearm extensors

    Origin: Lateral epicondyle of humerus.
    Main action: Extends wrist and digits.

  • External Oblique

    Origin: Outer surfaces of lower eight ribs (ribs 5–12).
    Main action: Flexes vertebral column, compresses abdominal wall, aids trunk rotation and lateral flexion.

  • Internal Oblique

    Origin: Lumbar fascia, iliac crest, and inguinal ligament.
    Main action: Flexes vertebral column, compresses abdominal wall, aids trunk rotation.

  • Transversus Abdominis

    Origin: Inguinal ligament, lumbar fascia, cartilages of lower 6 ribs, and iliac crest.
    Main action: Compresses abdominal contents.

  • Rectus Abdominis

    Origin: Pubic crest and pubic symphysis.
    Main action: Flexes and rotates lumbar vertebral column; compresses abdominal contents.

  • Diaphragm

    Origin: Inferior internal surface of rib cage, sternum, costal cartilages of lower 6 ribs, lumbar vertebrae.
    Main action: Prime mover of inspiration; flattens on contraction to increase thoracic cavity volume.

  • External intercostals

    Action: Elevates ribs for inspiration.

  • Internal intercostals

    Action: Depresses ribs for forced expiration.

  • Psoas Major

    Origin: Transverse processes, bodies, and intervertebral discs of T12–L5 vertebrae.
    Main action: Prime mover for flexing thigh.

  • Iliacus

    Origin: Iliac fossa and crest, lateral sacrum.
    Main action: Prime mover for flexing thigh.

  • Erector Spinae & Splenius

    Origin: Iliac crest, transverse and spinous processes of lumbar/thoracic vertebrae, lower ribs.
    Main action: Extends and laterally flexes vertebral column and head.

  • Gluteal group

    Origin: Dorsal ilium, sacrum, coccyx.
    Main action: Extends, abducts, and medially/laterally rotates thigh.

  • Adductor group

    Origin: Pubis and ischium.
    Main action: Adducts, flexes, and medially rotates thigh.

  • Hamstrings

    Origin: Ischial tuberosity (and linea aspera for short head of biceps femoris).
    Main action: Extends thigh at hip and flexes leg at knee.

  • Quadriceps group

    Origin: Anterior inferior iliac spine, superior margin of acetabulum, shaft of femur.
    Main action: Powerful knee extensor; rectus femoris also flexes thigh at hip.

  • Sartorius

    Origin: Anterior superior iliac spine.
    Main action: Flexes, abducts, laterally rotates thigh; flexes knee.

  • Tensor Fasciae Latae

    Origin: Anterior iliac crest and anterior superior iliac spine.
    Main action: Steadies knee and trunk on thigh; abducts and medially rotates thigh.

  • Gastrocnemius

    Origin: Medial and lateral condyles of femur.
    Main action: Plantar flexes foot when knee extended; flexes knee.

  • Soleus

    Origin: Superior tibia, fibula, and interosseous membrane.
    Main action: Plantar flexes foot.

  • Tibialis Anterior

    Origin: Lateral condyle and upper 2/3 of tibia; interosseous membrane.
    Main action: Prime mover of dorsiflexion; inverts foot.

  • Fibularis (Peroneus)

    Origin: Head and lateral shaft of fibula.
    Main action: Plantar flexes and everts foot.

  • Posterior lower leg flexors

    Origin: Posterior shaft of tibia, fibula, and interosseous membrane.
    Main action: Plantar flexes and inverts foot; flexes toes.

  • Anterior lower leg extensors

    Origin: Lateral condyle of tibia, shaft of fibula, and interosseous membrane.
    Main action: Dorsiflexes foot; extends toes.